Abstract
Nine field experiments were conducted to explore the feasibility of maize and legumes fodder production technology in the existing cropping pattern without or minimum yield loss of main crops, at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymemsingh from July 2006 to June 2008. The experimental land was medium high in topography having non-calcareous dark grey soil under Agro-ecological zone (AEZ-9). The soil status of the experimental plot was characterized by silt loam in texture, slightly acidic, organic matter below 1.50 % and other nutrients content were medium to low. The climate of the experimental site was wet, humid and sub-tropical. Main characteristics of the climate are heavy monsoon rainfall, short winter and long dry spell in pre-monsoon. Transplant Aman rice, grasspea grain, wheat, Aus rice and Capsularis jute were the main and maize, cowpea, grasspea and blackgram were the fodder crops in the six seasons of two years experimentation as relay or inter- cropping system. One experiment, cowpea fodder at various seed rates intercropped with wheat was ' repeated in the second year for recording some growth parameters and confirmation of previous year's findings. All the experiments were laid out in a randomized complete block design with three replications and the size of unit plots were 4.0 m x 2.5 m. The main and fodder crops were planted at various spacings or densities as sole crop for comparison. Growth parameters, yield components and yields were higher in case of sole cropping of main and fodder crops. Leaf area index; integrated leaf area index; total dry matter and crop growth rate of wheat and cowpea were the highest from 40 DAS up to immediately before harvest when cowpea was intercropped at 70 kg seed ha' with wheat. Economic study on gross return, net return and benefit cost ratio were done on the basis of prevailing market price of inputs and commodities produced. Relay or intercropping systems always showed better performance in terms of gross and net return; benefit cost ratio and land equivalent ratio compared to sole cropping of main or fodder crops at various plant population unit area. Proximate components viz. dry matter was significantly affected in maize and not significantly affected in cowpea, grasspea and blackgram and crude protein was significantly affected in maize, cowpea and grasspea and not significantly affected in blackgram. Crude fiber was significantly affected in grasspea and not significantly affected in maize, cowpea and blackgram; ether extract was significantly affected in cowpea and blackgram and not significantly affected in maize and grasspea and ash content was significantly affected in maize and grasspea and not significantly affected in cowpea and blackgram. Nitrogen free extract and organic matter content of maize, cowpea, grasspea and blackgram fodder were not significantly affected by relay or intercropping with main crops or sole cropping of fodder crops at different densities. With minimum grain yield loss and higher monetary benefit, maize fodder was grown successfully by means of relay cropping at 25 cm x 15 cm spacing in transplant Aman rice, which was relayed with grasspea grain, intercropping at 25 cm x 30 cm spacing with wheat sown in row (25 cm row to row) system and at 75 cm × 25 cm spacing in Aus rice (sown in 25 cm apart lines). Maize fodder also was grown successfully with no significant fibre yield loss but with higher monetary benefit at 75 cm x 25 cm spacing in Capsularis jute sown in line (25 cm x 5 cm). Cowpea fodder intercropping at 70 kg seed ha' with wheat sown in row (25 cm row to row) and with Aus rice sown in 25 cm apart lines at 70 kg seed ha"; grasspea relaying as fodder crop at 90 kg seed ha1 in transplant Aman rice and blackgram fodder intercropping at 50 kg seed ha in Aus rice row sowing (25 cm row to row) would be the promising fodder production technologies because of higher monetary benefit and minimum grain yield loss.